The production of yarn having different dyes spaced along its length is termed "space dyeing." Space-dyed yarns are desirable because they easily may be formed into textile fabrics that have an inherent random or pseudo-random pattern imparted by the patterning of the yarns comprising the fabric. While other methods of imparting a similar pattern to textile fabrics are well known, they are more difficult and require more steps than the present invention.
Several methods for space dyeing of yarns are known. Among batch-type processes (in which a predetermined quantity of yarn is treated at one time), for example, it is known to inject yarn packages with a number of different colored dyes to yield a space-dyed product. However, such batch processes are often more costly and require more product handling than continuous processes. Continuous space-dyeing processes (in which moving yarns are individually or collectively treated) are also known. Typically, dye may be applied by a series of rollers, or may be sprayed on individual yarns or yarn sheets. While generally more efficient than package dyeing techniques, these continuous dyeing processes often experience difficulties with dye mist and drips, resulting in unwanted marks and wasted dye liquor. Furthermore, dye overspray from the various colors being applied often mixes together in a single collection system and must be discarded, resulting in added costs for replacement dye as well as for waste handling and disposal.
In addition to the problems recounted above, none of these methods has been able to solve the problems of imperfect registration of the dye pattern. That is, often the yarns produced by these methods exhibit undesirable undyed areas, or areas in which an overlapping of different dyes results in undesirable colorations. Attempts to eliminate undyed areas by providing a constant overspray of dye have resulted in the use of more dye than the instant invention, resulting in a higher cost per pound of yarn, in addition to the necessity of adjusting dye formulations to compensate for the color imparted by the overspray. Such attempts also tend to exacerbate the problem of undesirable overlapping of adjacent dyed areas, and lead to space-dyed yarns in which the overall result is neither predictable nor controllable.